Placement of lumiphores within a light emitting resonator in a visual display with electro-optical addressing architecture

ABSTRACT

A display device and method of operating the display device. The display device comprising a support substrate, a plurality of ring or disk shaped light emitting light emitting resonators placed in a matrix on the support substrate forming a plurality of rows and columns of the light emitting resonators, each of said light emitting resonators having photo-luminescent lumiphore placed in the outer portion of said ring or disk shaped light emitting resonators A plurality of light waveguides positioned on the substrate such that each of the light emitting resonators is associated with an electro-coupling region with respect with to one of the plurality of light waveguides and a deflection mechanism for causing relative movement between a portion of at least one of the plurality of light waveguides and the associated light emitting resonator so as to control when the light emitting resonator is in the electro-coupling region. A light source is associated with each of the plurality of light waveguides for transmitting a light along the plurality of light waveguides for selectively activating each of the light emitting resonators when positioned within the electro-coupling region.

CROSS REFERENCE TO RELATED APPLICATIONS

U.S. Ser. No. ______, filed concurrently herewith, of John P.Spoonhower, and David Lynn Patton entitled “Visual Display WithElectro-Optical Addressing Architecture”, Atty. Docket No. 88841/F-P;

U.S. Ser. No. ______, filed concurrently herewith, of John P.Spoonhower, David Lynn Patton and Frank Pincelli, entitled “VisualDisplay With Electro-Optical Individual Pixel Addressing Architecture”,Atty. Docket No. 89574/F-P; and

U.S. Ser. No. ______, filed concurrently herewith, of John P. Spoonhowerand David Lynn Patton, entitled “Polarized Light Emitting Source With AnElectro-Optical Addressing Architecture”, Atty. Docket No. 89582/F-P;

FIELD OF THE INVENTION

The placing of lumiphores in light emitting resonators in a flat panelvisible display wherein optical waveguides and other thin filmstructures are used to distribute (address) excitation light to apatterned array of visible light emitting pixels.

BACKGROUND OF THE INVENTION

A flat panel display system is based on the generation ofphoto-luminescence within a light cavity structure. Optical power isdelivered to the light emissive pixels in a controlled fashion throughthe use of optical waveguides and a novel addressing scheme employingMicro-Electro-Mechanical Systems (MEMS) devices. The energy efficiencyof the display results from employing efficient, innovativephoto-luminescent species in the emissive pixels and from an opticalcavity architecture, which enhances the excitation processes operatinginside the pixel. The present system is thin, light weight, powerefficient and cost competitive to produce when compared to existingtechnologies. Further advantages realized by the present system includehigh readability in varying lighting conditions; high color gamut;viewing angle independence, size scalability without brightness andcolor quality sacrifice, rugged solid-state construction, vibrationinsensitivity and size independence. The present invention has potentialapplications in military, personal computing and digital HDTV systems,multi-media, medical and broadband imaging displays and large-screendisplay systems. Defense applications may range from full-color,high-resolution, see-through binocular displays to 60-inch diagonaldigital command center displays. The new display system employs thephysical phenomena of photo-luminescence in a flat-panel display system.

Previously, Newsome disclosed the use of upconverting phosphors andoptical matrix addressing scheme to produce a visible display in U.S.Pat. No. 6,028,977. Upconverting phosphors are excited by infraredlight; this method of visible light generation is typically lessefficient than downconversion (luminescent) methods like directfluorescence or phosphorescence, to produce visible light. Furthermore,the present invention differs from the prior art in that a differentaddressing scheme is employed to activate light emission from aparticular emissive pixel. The method and device disclosed herein doesnot require that two optical waveguides intersect at each light emissivepixel. Furthermore, novel optical cavity structures, in the form ofoptical light emitting resonators, are disclosed for the emissive pixelsin the present invention.

Additionally, in US Patent Application Publication US2002/0003928A1,Bischel et. al. discloses a number of structures for coupling light fromthe optical waveguide to a radiating pixel element. The use ofreflective structures to redirect some of the excitation energy to theemissive medium is disclosed. In the present invention, we disclose theuse of novel optical cavity structures, in the form of ring or diskresonators, the resonators themselves modified to affect the emission ofvisible light.

The use of such resonators further allows for a novel method of controlof the emission intensity, through the use of Micro-Electro-MechanicalSystems (MEMS) devices to alter the degree of power coupling between thelight power delivering waveguide and the emissive resonator pixel. Suchmeans have been disclosed in control of the power coupling toopto-electronic filters for telecommunications applications. In thiscase, the control function is used to tune the filter. Control over thepower coupling is described in “A MEMS-Actuated Tunable MicrodiskResonator”, by Ming-Chang M. Lee and Ming C. Wu, paper MC3, 2003IEEE/LEOS International Conference on Optical MEMS, 18-21 August 2003.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is provideda display device, comprising:

a. a support substrate;

b. a plurality of ring or disk shaped light emitting resonators placedin a matrix on the support substrate forming a plurality of rows andcolumns of the light emitting resonators, each of said light emittingresonators having photo-luminescent lumiphore placed in the outerportion of said ring or disk shaped light emitting resonators;

c. a plurality of light waveguides positioned on the substrate such thateach of the light emitting resonators is associated with anelectro-coupling region with respect with to one of the plurality oflight waveguides;

d. a deflection mechanism for causing relative movement between aportion of at least one of the plurality of light waveguides and theassociated light emitting resonator so as to control when the lightemitting resonator is in the electro-coupling region; and

e. a light source associated with each of the plurality of lightwaveguides for transmitting a light along the plurality of lightwaveguides for selectively activating each of the light emittingresonators when positioned within the electro-coupling region.

In accordance with another aspect of the present invention there isprovided a method for controlling visible light emitting from a displaydevice having plurality of ring or disk shaped light emitting resonatorsplaced in a pattern forming a plurality of rows and columns and aplurality of wave light guides positioned so that each of the lightemitting resonators is positioned adjacent one of the plurality of wavelight guides, each of said light emitting resonators havingphoto-luminescent lumiphore placed in the outer portion of said ring ordisk shaped light emitting resonators; comprising the steps of:

a. providing a light source associated with each of the plurality oflight waveguides for transmitting a light along the associated lightwaveguide;

b. providing deflection mechanism for causing relative movement betweena portion of at least one of the plurality of light waveguides and theassociated light emitting resonator so as to control when the lightemitting resonator is in the electro-coupling region;

c. selectively controlling emission of visible light from the pluralityof light emitting resonators by controlling the deflection mechanism andlight source such that when the light emitting resonator in theelectro-coupling region and a light is transmitted along the associatedlight waveguide the emission of visible light will occur.

These and other aspects, objects, features and advantages of the presentinvention will be more clearly understood and appreciated from a reviewof the following detailed description of the preferred embodiments andappended claims and by reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will become more apparent when taken in conjunction with thefollowing description and drawings wherein identical reference numeralshave been used, where possible, to designate identical features that arecommon to the figures, and wherein:

FIG. 1 is a schematic top view of an optical flat panel display made inaccordance with the present invention;

FIGS. 2A, 2B and 2C are enlarged top plan views of red light, greenlight and blue light emitting resonators for a color display made inaccordance with the present invention;

FIG. 3 is an enlarged cross-sectional view of the optical waveguide astaken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged cross-sectional schematic view of the opticalwaveguide showing the electrode geometry and electrostatic forces;

FIG. 5 is an enlarged perspective view of a portion of the display ofFIG. 1 showing a single ring resonator; single associated opticalwaveguide and electrodes;

FIGS. 6A, B and C are enlarged cross-sectional views of the display ofFIG. 5 taken along line 6-6 of FIG. 5, which shows the location of aMEMS device used to control the pixel intensity at various intensitypositions;

FIG. 7 is an enlarged cross-sectional view of the waveguide andresonator elements showing an alternative embodiment for thelight-emissive resonator;

FIG. 8 is an enlarged top plan view showing an alternative resonatorembodiment in the form of a disk:

FIG. 9 is an enlarged cross-sectional view taken along line 9-9 of FIG.5 of the resonator elements showing the placement of lumiphores withinthe light-emissive resonator, and

FIG. 10 is an enlarged cross-sectional view of the display of FIG. 5taken along line 10-10 of FIG. 5, which shows the location of alumiphore(s) in relationship to the waveguide and the light emittingresonator.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-2 there is illustrated a photo-luminescent display5 system made in accordance with the present invention. The displaysystem functions by converting excitation light to emitted, visiblelight. In the embodiment illustrated, each pixel 10 in display 5 iscomprised of one or more sub-pixels; sub-pixels are typically comprisedof a red sub-pixel 11, a green sub-pixel 12, and a blue sub-pixel 13, asshown in FIG. 2. Colors other than red, green, and blue are caused bythe admixture of these primary colors thus controlling the intensity ofwhich the individual sub-pixels adjusts both the brightness and color ofa pixel 10. Those skilled in the art understand that other primary colorselections are possible and will lead to a full color display. Colorgeneration in the display is a consequence of the mixing ofmultiple-wavelength light emissions by the viewer. This mixing isaccomplished by the viewer's integration of spatially distinct,differing wavelength light emissions from separate sub-pixels that arebelow the spatial resolution limit of the viewer's eye. Typically acolor display has red, green, and blue separate and distinct sub-pixels,comprising a single variable color pixel. Monochrome displays may beproduced by the use of a single color pixel 10 or sub-pixel 11, 12, 13,or by constructing a single pixel capable of emitting “white” light. Thespectral characteristics of a monochrome display pixel will bedetermined by the choice of lumiphore or combination of lumiphores.White light generation can be accomplished through the use of multipledoping schemes for the light emitting resonator 30 as described byHatwar and Young in U.S. Pat. No. 6,727,644 B2. Photo-luminescence isused to produce the separate wavelength emission from each pixel (orsubpixel) element. The photo-luminescence may be a result of a number ofphysically different processes including, multi-step, photonicup-conversion processes and the subsequent radiative emission process,direct optical absorption and the subsequent radiative emission process,or optical absorption followed by one or more energy transfer steps, andfinally, the subsequent radiative emission process. Use of combinationsof these processes may also be considered to be within the scope of thisinvention.

FIG. 1 is schematic top view of an optical flat panel display 5 made inaccordance with the present invention. The display 5 contains an array 7of light emitters comprised of a matrix of pixels 10 each having a lightemitting resonator 30 (shown in FIGS. 2A, B, and C) located at eachintersection of an optical row waveguide 25 and column electrodes 28. Apower source 22 is used to activate the light source array 15. The lightsource array 15 provides optical power or light 20, used to excite thephoto-luminescent process in each pixel 10. Typical light source arrayelements 17 may be diode lasers, infrared laser, light emitting diodes(LEDs), and the like. These may be coherent or incoherent light sources.These light sources may be visible, ultraviolet, or infrared lightsources. There may be a one-to-one correspondence between the lightsource array element 17, and an optical row waveguide 25, oralternatively, there may be a single light source array element 17multiplexed onto a number of optical row waveguides 25, through the useof an optical switch to redirect the light 20 output from the singlelight source array element 17.

A principal component of the photo-luminescent flat panel display system5 is the optical row waveguide 25, also known as a dielectric waveguide.Two key functions are provided by the waveguides 25. They confine andguide the optical power to the pixel 10. Several channel waveguidestructures have been illustrated in U.S. Pat. No. 6,028,977. The opticalwaveguides must be restricted to TM and TE propagation modes. TM and TEmode means that optical field orientation is perpendicular to thedirection of propagation. Dielectric waveguides confining the opticalsignal in this manner are called channel waveguides. The buried channeland embedded strip guides are applicable to the proposed displaytechnology. Each waveguide consists of a combination of cladding andcore layer. These layers are fabricated on either a glass-based orpolymer-based substrate. The core has a refractive index greater thanthe cladding layer. The core guides the optical power past the resonatorin the absence of power coupling. With the appropriate adjustment of thedistance between the optical row waveguide 25 and the light emittingresonator 30, power is coupled into the light emitting resonator 30. Atthe light emitting resonator 30 the coupled optical light power drivesthe resonator materials into a luminescent state. The waveguides 25 andresonators 30 can be fabricated using a variety of conventionaltechniques including microelectronic techniques like lithography. Thesemethods are described, for example, in “High-Finesse Laterally CoupledSingle-Mode Benzocyclobutene Microring Resonators” by W.-Y. Chen, R.Grover, T. A. Ibrahim, V. Van, W. N. Herman, and P.-T. Ho, IEEEPhotonics Technology Letters, 16(2), p. 470. Other low-cost techniquesfor the fabrication of polymer waveguides can be used such asimprinting, and the like. Nano-imprinting methods have been described in“Polymer Microring Resonators Fabricated By Nanoimprint Technique” byChung-yen Chao and L. Jay Gao, J. Vac. Sci. Technol. B 20(6), p. 2862.Photobleaching of polymeric materials as a fabrication method has beendescribed by Joyce K. S. Poon, Yanyi Huang, George T. Paloczi, and AmnonYariv, in “Wide-Range Tuning Of Polymer Microring Resonators By ThePhotobleaching Of CLD-1 Chromophores” by, Optics Letters 29(22), p.2584. This is an effective method for post fabrication treatment ofoptical micro-resonators. A wide variety of polymer materials are usefulin this and similar applications. Theses can include fluorinatedpolymers, polymethylacrylate, liquid crystal polymers, and conductivepolymers such as polyethylene dioxythiophene, polyvinyl alcohol, and thelike. These materials and additionally those in the class of liquidcrystal polymers are suitable for this application (see “Liquid CrystalPolymer (LCP) for MEMs”, by X. Wang et. al., J. Micromech. MicroEng, 13,(2003), p. 628-633.) This list is not intended to be all inclusive ofthe materials that may be employed for this application.

Excitation of the light emitting resonator 30 (shown in FIGS. 2A, B, andC) by the row waveguide 25 under the control of the column voltagesource 18 and column electrodes 28 causes the light emitting resonator30 to emit visible light. The excitation of the light emitting resonator30 is caused by optical pumping action of the light 20 shown in FIG. 1from a row light source array element 17 through the row waveguide 25and controlling voltage to the column electrodes 28 by multiplexcontroller 19 from a column voltage source 18. The excitation process isa coordinated row-column, electrically activated, optical pumpingprocess called electro-optical addressing. Those skilled in the art knowthat the roles of columns and rows are fully interchangeable withoutaffecting the performance of this display 5.

Now referring to FIG. 2A, electro-optical addressing is defined as amethod for controlling an array 7 (not shown) of light emittingresonators 30 that form the optical flat panel display 5 (see FIG. 1).In FIG. 2A, a pixel 10 comprised of three sub-pixels, 11, 12, and 13 isshown. In electro-optical addressing, the selection of a particularpixel that appears to be light emitting is accomplished by the specificcombination of excitation of light in a particular optical row waveguide25, and voltage applied to a particular set of column electrodes 28.

The light emitting resonator 30 is excited into a photo-luminescentstate through the absorption of light 20 as a result of the closeproximity to the row waveguides 25. The physics of the coupling ofenergy between the resonator 30 and the optical row waveguide 25 is wellknown in the art. It is known to depend critically upon the optical pathlength between the row waveguide 25 and the light emitting resonator 30;it can therefore be controlled by the distance (h, shown in FIGS. 6A and6B) separating the two structures or by various methods of controllingthe index of refraction. Typical methods for control of the index ofrefraction include heat, light, and electrical means; these are wellknown. These methods correspond respectively to the thermo-optic,photorefractive, and electro-optic methods. The invention disclosedherein makes use of control of the distance parameter via a MEMS deviceto control the energy coupling, and thus affect the intensity ofphoto-luminescent light generated in the pixel 10. In an example, thelight emitting resonator 30 is composed of a light transmissive materialbut incorporating (doped with) a light emitting photo-luminescentspecies. The base material (the material excluding the photo-luminescentspecies or dopant) for the light emitting resonator may be the same ordifferent from the optical row waveguide 25 material. Typical basematerials can include glasses or polymers.

Photo-luminescent species or dopants can include various fluorophores,or phosphors including up-converting phosphors. The selection of aparticular dopant or dopants will primarily determine the emissionspectrum of a particular light emitting resonator 30. These lumiphores(fluorophores or phosphors) may be inorganic materials or organicmaterials. The light emitting resonator 30 can include a combination ofdopants that cause it to respond to the electro-optic addressing byemitting visible radiation. Dopant or dopants include the rare earth andtransition metal ions either singly or in combinations, organic dyes,light emitting polymers, or materials used to make Organic LightEmitting Diodes (OLEDs). Additionally, lumiphores can include suchhighly luminescent materials such as inorganic chemical quantum dots,such as nano-sized CdSe or CdTe, or organic nano-structured materialssuch as the fluorescent silica-based nanoparticles disclosed in USPatent Application Publication US 2004/0101822 Al by Wiesner and Ow. Theuse of such materials is known in the art to produce highly luminescentmaterials. Single rare earth dopants that can be used are erbium (Er),holmium, thulium, praseodymium, neodymium (Nd) and ytterbium. Somerare-earth co-dopant combinations include ytterbium:erbium,ytterbium:thulium and thulium:praseodymium. Single transition metaldopants are chromium (Cr), thallium (Tl), manganese (Mn), vanadium (V),iron (Fe), cobalt (Co) and nickel (Ni). Other transition metal co-dopantcombinations include Cr:Nd and Cr:Er. The upconversion process has beendemonstrated in several transparent fluoride crystals and glasses dopedwith a variety of rare-earth ions. In particular, CaF₂ doped with Er³⁺.In this instance, infrared upconversion of the Er3+ ion can be caused toemit two different colors: red (650 nm) and green (550 nm). The emissionof the system is spontaneous and isotropic with respect to direction.Organic fluorophores can include dyes such as Rhodamine B, and the like.Such dyes are well known having been applied to the fabrication oforganic dye lasers for many years. The preferred organic material forthe light emitting resonator 30 is a small-molecular weight organichost-dopant combination typically deposited by high-vacuum thermalevaporation. It is also preferred that the host materials used in thepresent invention are selected such that they have sufficient absorptionof the excitation light 20 and are able to transfer a large percentageof their excitation energy to a dopant material via Förster energytransfer. Those skilled in the art are familiar with the concept ofFörster energy transfer, which involves a radiationless transfer ofenergy between the host and dopant molecules. An example of a usefulhost-dopant combination for red-emitting lasers is aluminumtris(8-hydroxyquinoline) (Alq) as the host and[4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran](DCJTB) as the dopant (at a volume fraction of 1%). Other host-dopantcombinations can be used for other wavelength emissions. For example, inthe green a useful combination is Alq as the host and[10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]Benzopyrano[6,7,8-ij]quinolizin-11-one](C545T) as the dopant (at a volume fraction of 0.5%). Other organiclight emitting materials can be polymeric substances, e.g.,polyphenylenevinylene derivatives, dialkoxy-polyphenylenevinylenes,poly-para-phenylene derivatives, and polyfluorene derivatives, as taughtby Wolk et al. in commonly assigned U.S. Pat. No. 6,194,119 B1 andreferences therein.

Electro-optical addressing employs the optical row waveguide 25 todeliver light 20 to a selected light emitting resonator 30. The lightemitting resonator 30 is the basic building block of the optical flatpanel display 5. Referring now to FIGS. 2A, 2B, and 2C, an enlarged topview of a red light 41, green light 42 and blue light 43 light emittingresonator 30 respectively, is illustrated respectively in these figures.Using the red light 41, green light 42 and blue light 43 light emittingresonators to create red 11, green 12, and blue 13 pixels, a full coloroptical flat panel display 5 can be formed. The wavelength of theemission of the red 41, green 42 and blue 43 light is controlled by thetype of material used in forming the light emitting resonators 30.Selection of a particular pixel 10 or sub-pixel (11-13) is based uponthe use of a MEMS device to alter the distance and affect the degree ofpower transfer of light 20 to the light emitting resonator 30. Note thatin each instance, light 20 is directed within an appropriate optical rowwaveguide 25 to excite a particular light emitting resonator 30. Throughthe combination of excitation specific optical row waveguide with light20 and excitation of a specific MEMS device, controlled by the columnelectrodes 28, a particular pixel 10 (subpixel) is excited. The lightemitting resonator 30 may take the form of a micro-ring or a micro-disk.These forms are shown in FIGS. 2 and 5, respectively. Note that in orderfor the light emitting resonator 30 to produce sufficient light to beviewable, the resonator 30 must be fabricated in a manner so that it is‘leaky”; there are a number of methods to accomplish this lowering ofthe cavity Q, including but not limited to increasing the surfaceroughness of the resonator cavity surface. Additionally, one could lowerthe refractive index of the material comprising the light emittingresonator 30.

The substrate or support 45 (see FIG. 3) can be constructed of either asilicon, glass or a polymer-based substrate material. A number of glassand polymer substrate materials are either commercially available orreadily fabricated for this application. Such glass materials include:silicates, germanium oxide, zirconium fluoride, barium fluoride,strontium fluoride, lithium fluoride, and yttrium aluminum garnetglasses. A schematic of an enlarged cross-sectional view of the opticalflat panel display 5 taken along the line 3-3 of FIG. 2 is shown in FIG.3. The column electrodes 28 are not shown for simplicity. On a substrate45 is formed a layer 35 containing the optical row waveguide 25 and thelight emitting resonator. For such a buried-channel waveguide structureit is imperative that the refractive index of optical row waveguide 25(the core) be greater than the surrounding materials, in this instancethe layer 35. The layer 35 acts as the cladding region in thisembodiment. An optional layer 32 is shown, this may be of a relativelylower index material in order to better optically isolate the opticalrow waveguide 25. A top layer 52 is provided on the top surface 47 oflayer 35 for protection of the underlying structures. In the case ofFIG. 3 the entire structure is shown surrounded by air 55.

Integrated semiconductor waveguide optics and microcavities have raisedconsiderable interest for a wide range of applications, particularly fortelecommunications applications. The invention disclosed herein appliesthis technology to electronic displays. As stated previously, the energyexchange between cavities and waveguides is strongly dependent on thespatial distance. Controlling the distance between waveguides andmicrocavities is a practical method to manipulate the power coupling andhence the brightness of a pixel 10 or sub-pixel (11-13).

An ideal resonator or cavity has characteristics of high quality factor(which is the ratio of stored energy to energy loss per cycle) and smallmode volume. Dielectric micro-sphere and micro-toroid resonators havedemonstrated high quality factors. Micro-cavities possess potential toconstruct optical resonators with high quality factor and ultra-smallmode volume due to high index-contrast confinement. Small mode volumeenables small pixel 10 or sub-pixel (11-13) dimensions, consistent withthe requirements of a high resolution display. A MEMS device structurefor affecting the amount of light 20 coupled into a light emittingresonator 30 is shown in FIG. 4. FIG. 4 is an enlarged cross-sectionalview of the optical waveguide showing the electrode geometry, fieldlines 46, and resulting downward electrostatic force 44 for affectingthe power coupling change. MEMS actuators using electrostatic forces inthis instance, move a waveguide to change the distance h, shown in FIG.6A between a resonator and the optical row waveguide 25, resulting in awide tunable range of power coupling ratio by several orders ofmagnitude which is difficult to achieve by other methods. Based on thismechanism, the micro-disk/waveguide system can be dynamically operatedin the under-coupled, critically-coupled and over-coupled condition.

In high-Q micro-resonators, varying the gap spacing or distance h,between the waveguide and the micro-disk or micro-ring resonator bysimply a fraction of a micron leads to a very significant change in thepower transfer to the light emitting resonator 30 from the optical rowwaveguide 25. FIG. 5 is an enlarged perspective view of the display ofFIG. 1 showing a light emitting ring resonator 30; optical waveguide 25,and electrodes 28. As shown in FIG. 5, a suspended waveguide is placedin close proximity to the micro-ring or micro-toroid light emittingresonator 30. The initial gap (not shown) (˜1 μm wide) is large so thereis no coupling between the waveguide and the resonator. Referring toFIG. 5, the suspended optical row waveguide 25 can be pulled towards themicro ring resonator by four electrostatic gap-closing actuators, theelectrodes 28. Therefore, the coupling coefficient can be varied byapplied voltage. For high index-contrast waveguides, the couplingcoefficient is very sensitive to the critical distance. 1-umdisplacement can achieve a wide tuning range in power coupling ratio,which is more than five orders of magnitude. Typically, the radius ofmicro-ring resonator is 10 μm and the width of waveguide is 0.7 μm. Butthese sizes may vary depending upon the display type and application. InFIG. 5 the optical waveguide 25 is shown displaced downward so as toaffect a maximum power transfer to the light emitting resonator 30.

FIG. 6A is an enlarged cross-sectional view of the display of FIG. 5,which shows the location of a MEMS device used to control the pixelintensity. The area surrounding the optical row waveguide 25 and thelight emitting ring resonator 30 has been etched back to expose the topsurfaces 48 to air 55. The optical row waveguide 25 is aligned to theedge of the light emitting resonator 30 and vertically displaced topreclude a high degree of coupling. The waveguide 25 is electricallygrounded and actuated by a pair of electrodes 28 at the two ends, whichforms an electro-coupling region 58. Due to the electrostatic force, thewaveguide is pulled downward toward the light emitting resonator 30,resulting in the decreased gap-spacing, h. The optical row waveguide 25is shown in the rest position d in FIG. 6A. In FIG. 6A, the distancebetween the optical row waveguide 25 and the light emitting ringresonator 30 is large; coupling of light into the light emittingresonator 30 is precluded and there is no light emission from the pixel.

Initially, in the absence of the application of the control voltage, theoptical row waveguide 25 is separated from the light emitting resonatorby a distance significantly greater than the critical distance “h_(c)”31 (see FIG. 6C) and hence there is no light emission from the lightemitting resonator 30. In FIG. 6B, the vertical distance d′ is shownwhere there exists a degree of coupling between the optical rowwaveguide 25 and the light emitting ring resonator 30, and hence lightemission from the pixel occurs. By varying the distance d′, theintensity of the light emission from the pixel can be varied in acontrollable manner. In FIG. 6C, the distance d″ is shown thatcorresponds to the displacement of the optical row waveguide 25necessary to place the optical row waveguide 25 at the critical couplingdistance h_(c) and thereby optimize power coupling. This configurationwill produce the maximum emitted light intensity from the pixel. Notethat light emitting resonator is shown with a roughened surface 60; thiswill be discussed below. The optical row waveguide can be fabricatedfrom silicon appropriately doped to provide electrical conductivity.Alternatively, the optical row waveguide can be fabricated from otheroptically transparent conductive materials such as polymers that meetthe optical index of refraction requirement disclosed above.

In the embodiment shown in FIG. 6C, the light emitting resonator 30 isshown spaced the critical distance 31, h_(c) from the optical rowwaveguide 25. Excitation light 20 is emitted from top roughened surface60 of the light emitting resonator 30, which causes the light emittingresonator to leak light and become visible to a viewer. As shown in FIG.6C, a light emitting layer 49 is placed within the light emittingresonator. This layer 49 contains photo-luminescent species orlumiphores 65 that absorb the pump or excitation light 20 and via theluminescence processes discussed above, produce the visible lightdirected to the viewer. The wavelength of the light produced in theemitting layer 49 is determined by the material composition aspreviously disclosed. The light emitting layer 49 may be formed on thetop surface of the light emitting resonator 30 as well as placed withinthe internal structure of the light emitting resonator as is shown inFIG. 6C. FIG. 6C shows the emitting layer 49 displaced vertically fromthe bottom surface 39 of light emitting resonator 30.

FIG. 7 is an enlarged cross-sectional view of the resonator elementsshowing an alternative embodiment for the light-emissive resonator 30.In this embodiment the lumiphores 65 are shown uniformly distributedwithin the light emitting resonator 30.

FIG. 8 is an enlarged top plan view showing an alternative resonatorembodiment in the form of a disk. The critical distance “h_(c)” 31 isshown as well as the light emitting disk 67 resonator. A number ofstructures have been demonstrated for the resonator element includingring, disk, elliptical and racetrack or oval structures. The coupling ofoptical power into such structures is well known to those skilled in theart. The use of such structures as light emitting resonators isconsidered within the scope of this invention.

FIG. 9 is an enlarged cross-sectional view of the resonator elements 30showing an alternative embodiment for the light-emissive resonator 30.In this case one or more of the lumiphores 65 are shown placed at theperiphery of the light emitting resonator 30. Theoretical modeling ofthe light intensity patterns within these resonators indicates thatthere are regions within the resonator where the light power isconcentrated. For example, “FDTD Microcavity Simulations: Design andExperimental Realization Of Waveguide-Coupled Single-Mode Ring andWhispering-Gallery-Mode Disk Resonators” by S. C. Hagness et. al.,Journal of Lightwave Technology, Vol. 15, No. 11, pgs. 2154-2165,disclose the intensity patterns within the resonator for a number of thelower order modes of excitation. These so-called whispering gallerymodes show a preferential distribution of light within the outer portionof the resonator. Typically the outer one third of the radius of amicro-disk or ring resonator is where the light power is concentrated.Of course larger resonator structures support many higher modes withinthe resonator resulting in a more uniform light intensity distribution.For small resonators, such as would be used in high resolution displayembodiments, a preferred embodiment of the current invention is shown inFIG. 9. Note that the lumiphores 65 are shown optimally placed in theouter third of the resonator structure in an emitting layer 49 to mostefficiently absorb the excitation light and produce visible lightemission. Additionally, the light emitting resonator 30, need only havea roughened surface 60 in the region above the light emitting layer 49.Also note that in both FIGS. 9 and 10, the layer 35 supporting the lightemitting resonator 30 undercuts the light emitting resonator. It isknown in the art that such undercutting is useful to facilitate thecreation of high Q resonators. This would be done in the presentembodiment to minimize light emission from the light emitting layer 49on the bottom side of the resonator.

FIG. 10 is an enlarged cross-sectional view of the display of FIG. 5,showing the relationship of the placement of one or more lumiphores 65in a light emitting layer 49 in the light emitting resonator 30 inrelationship to the waveguide 25.

The invention has been described with reference to a preferredembodiment; however, it will be appreciated that variations andmodifications can be affected by a person of ordinary skill in the artwithout departing from the scope of the invention. In particular, it iswell known in the art that the optical row waveguide 25 can be placedadjacent to the light emitting resonator 30 in the same horizontalplane, and tuned for power transfer by affecting a lateral, that isin-plane or horizontal displacement, rather than the verticaldisplacements depicted above. Additionally, it may be advantageous toplace the optical row waveguide 25 above the light emitting resonator 30adjacent to the periphery of the light emitting resonator 30. In thislatter case the electro-coupling region 58 would be placed verticallyabove the edge of the light emitting resonator 30 and power transferaffected by a vertical displacement of the optical row waveguide 25relative to the top surface of the light emitting resonator 30. Manyother such variations are possible and considered within the scope ofthis invention.

PARTS LIST

-   5 display-   7 array-   10 pixel-   11 red sub-pixel-   12 green sub-pixel-   13 blue sub-pixel-   15 light source array-   17 light source array element-   18 column voltage source-   19 multiplex controller-   20 light-   22 power source-   25 row waveguide-   28 column electrodes-   30 light emitting resonator-   31 critical distance-   32 optional layer-   35 layer-   39 bottom surface of light emitting resonator-   41 red light-   42 green light-   43 blue light-   44 force-   45 substrate/support-   46 field lines-   47 top surface-   48 top surface-   49 emitting layer-   52 top layer-   55 air-   58 electro-coupling region-   60 roughened surface-   65 lumiphores-   67 light emitting resonator disk

1. A display device, comprising: a. a support substrate; b. a pluralityof ring or disk shaped light emitting resonators placed in a matrix onsaid support substrate forming a plurality of rows and columns of saidlight emitting resonators, each of said light emitting resonators havingphoto-luminescent lumiphore placed in the outer portion of said ring ordisk shaped light emitting resonators; c. a plurality of lightwaveguides positioned on said substrate such that each of said lightemitting resonators is associated with an electro-coupling region withrespect with to one of said plurality of light waveguides; d. adeflection mechanism for causing relative movement between a portion ofat least one of said plurality of light waveguides and said associatedlight emitting resonator for controlling when said light emittingresonator is in said electro-coupling region; and e. a light sourceassociated with each of said plurality of light waveguides fortransmitting a light along said plurality of light waveguides forselectively activating each of said light emitting resonators whenpositioned within said electro-coupling region.
 2. A display deviceaccording to claim 1 wherein said photo-luminescent lumiphore is placedin the outer third of said ring or disk.
 3. A display device accordingto claim 1 wherein the surface area over said photo-luminescentlumiphore is roughened.
 4. A display device according to claim 1 whereinphoto-luminescent lumiphore is provided in a continuous verticallythrough said ring or disk.
 5. A display device according to claim 4wherein the surface area over said photo-luminescent lumiphore isroughened.
 6. A display device according to claim 1 further comprising asupport layer supporting said light emitting resonator, said supportinglayer being undercut in the area beneath said ring or disk.
 7. A displaydevice according to claim 1 wherein said light source comprises aninfrared light source.
 8. A display device according to claim 7 whereinsaid infrared light source comprises a laser infrared light source.
 9. Adisplay device according to claim 1 wherein said light source comprisesa light emitting diode.
 10. A display device according to claim 6wherein said comprises a photo-luminescent lumiphore.
 11. A displaydevice according to claim 3 wherein an emissive coating is provided oversaid roughened surface.
 12. A display device according to claim 1wherein an overcoat is provided over said plurality of light emittingresonators and light waveguides.
 13. A display device according to claim1 wherein said deflection mechanism comprises at least one electrodeprovided for deflection said portion of said waveguides.
 14. A displaydevice according to claim 1 wherein said deflection mechanism comprisesat pair of electrode provided for deflection said portion of saidwaveguides.
 15. A display device according to claim 1 wherein saiddeflection mechanism comprises pair of electrodes disposed on both sidesof at least one of light emitting resonator and passing adjacent with atleast one of said of said plurality of light waveguides whereby whensaid at a voltage is applied across said pair of electrodes a field isproduced which causes said at least one waveguide to move into saidelectro-coupling region.
 16. A display device according to claim 15wherein a control mechanism is provided for controlling the amount ofvoltage across said pair of electrodes so as to control the distance inwhich said at least one waveguide moves into said electro-couplingregion so as to control the amount of emission from said associatedlight emitting resonator.
 17. A display device according to claim 1wherein said plurality of light emitting resonator are grouped into setswherein in each of said leaky resonators emit a different color.
 18. Adisplay device according to claim 1 wherein at least one said pluralityof ring shaped light emitting resonators is disc shaped.
 19. A methodfor controlling visible light emitting from a display device havingplurality of ring or disk shaped light emitting resonators placed in apattern forming a plurality of rows and columns and a plurality of wavelight guides positioned so that each of said light emitting resonatorsis positioned adjacent one of said plurality of wave light guides, eachof said light emitting resonators having photo-luminescent lumiphoreplaced in the outer portion of said ring or disk shaped light emittingresonators; comprising the steps of: a. providing a light sourceassociated with each of said plurality of light waveguides fortransmitting a light along said associated light waveguide; b. providingdeflection mechanism for causing relative movement between a portion ofat least one of said plurality of light waveguides and said associatedlight emitting resonator so as to control when said light emittingresonator is in said electro-coupling region; c. selectively controllingemission of visible light from said plurality of light emittingresonators by controlling said deflection mechanism and light sourcesuch that when said light emitting resonator in said electro-couplingregion and a light is transmitted along said associated light waveguidesaid emission of visible light will occur.
 20. The method according toclaim 19 wherein deflection mechanism for causing relative movementcomprises a pair of electrodes associated with each of said plurality oflight emitting resonators further comprises the step of controlling theamount of relative movement by controlling the voltage applied acrosssaid pair of electrodes.
 21. The method according to claim 19 whereinsaid light source comprises an infrared light source.
 22. The methodaccording to claim 21 wherein said infrared light source comprises alaser infrared light source.
 23. The method according to claim 19wherein said light source comprises a light emitting diode.
 24. Themethod according to claim 19 wherein said deflection mechanism comprisesat least one electrode provided for deflection said portion of saidwaveguides.
 25. The method according to claim 19 wherein said deflectionmechanism comprises at pair of electrode provided for deflection saidportion of said waveguides.
 26. The method according to claim 19 whereinsaid deflection mechanism comprises pair of electrodes disposed on bothsides of at least one of light emitting resonator and passing adjacentwith at least one of said of said plurality of light waveguides wherebywhen said at a voltage is applied across said pair of electrodes a fieldis produced which causes said at least one waveguide to move into saidelectro-coupling region.
 27. The method according to claim 26 wherein acontrol mechanism is provided for controlling the amount of voltageacross said pair of electrodes so as to control the distance in whichsaid at least one waveguide moves into said electro-coupling region forcontrolling the amount of emission from said associated light emittingresonator.
 28. The method according to claim 19 wherein at least one ofsaid plurality of ring or disk shaped light emitting resonators comprisea disc.